Utnapishtim is the Babylonian flood hero who builds a boat in the Epic of Gilgamesh and is often compared with Noah.
In the flood story embedded in the Epic of Gilgamesh, the god Ea warns Utnapishtim to build a large boat and preserve living creatures, family members, and skilled workers. Utnapishtim survives the catastrophic flood and later receives immortality. The episode appears in Tablet XI of the standard version of the epic.
The comparison with Noah arises from shared story elements: divine warning, construction of a large vessel, survival of a flood, preservation of life, and the release of birds. The two narratives are not identical, however. Their characters, settings, theological frameworks, and literary details differ.
The Epic of Gilgamesh is preserved in ancient Mesopotamian cuneiform traditions. The flood episode is also related to the older Atrahasis tradition, whose flood survivor is called Atrahasis. Thus Utnapishtim is the answer for Gilgamesh, not a different name for Noah.